1. Field of the Invention
The present invention relates to a body-insertable device system and an in-vivo observation method using a body-insertable device for being introduced into a subject and sequentially taking images in the subject.
2. Description of the Related Art
Recently, in a field of endoscopes, a capsule-shaped body-insertable device (for example, a capsule endoscope) including an imaging function and a radio communication function has been proposed and a body-insertable device system for obtaining an image in a subject using this capsule endoscope has been developed. In order to observe (inspect) inside a subject, a capsule endoscope is swallowed through, for example, a mouth of the subject. Then, until it is naturally discharged, it moves inside a body cavity, such as the stomach or small intestine according to their peristaltic movements and takes images in the subject every 0.5 seconds, for example.
While the capsule endoscope moves inside the subject, the images taken by the capsule endoscope are received via an antenna provided on a body surface of the subject and shown on an external image display. The image display includes a radio communication function for the capsule endoscope and an image memory function for sequentially storing images received from the capsule endoscope in the subject. A doctor or a nurse displays images stored in the image display, that is, images of digestive canal in the subject to observe (inspect) inside the subject and provides diagnosis.
As such a body-insertable device, there is an in-vivo sensing device having a specific gravity that allows the device to float in liquid introduced in a subject and taking an image of a body cavity as being carried by flow of the liquid in the body cavity of the subject (See PCT National Publication No. 2004-529718).
However, the above described conventional body-insertable device is moved in the subject by the flow of the liquid filling the body cavity so that it is often difficult to move actively without relying on the flow of the fluid and the position or direction of imaging field in the body cavity cannot be changed actively. Thus, it is often difficult to take an entire image of a desired observed region in the subject, for example, the digestive canal such as the stomach or large intestine and it becomes difficult to observe every part of the observed region. Accordingly, there have been problems that it takes long time to observe inside the subject and that there is a possibility of overlooking an affected area or a bleeding area in the observed region, for example.